[1] Natl Inst Stand & Technol, Div Polymers, Mat Sci & Engn Lab, Gaithersburg, MD 20899 USA
[2] Natl Inst Stand & Technol, Div Ceram, Mat Sci & Engn Lab, Gaithersburg, MD 20899 USA
[3] Univ Calif Berkeley, Dept Elect Engn & Comp Sci, Berkeley, CA 94720 USA
[4] Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA